
# echo 0 > /sys/class/pwm/pwmchip0/export
# echo 20000000 > /sys/class/pwm/pwmchip0/pwm0/period
# echo 1000000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
# echo "normal" > /sys/class/pwm/pwmchip0/pwm0/polarity
# echo 0 > /sys/class/pwm/pwmchip0/pwm0/enable